1. Field of the Invention
This invention relates generally to devices for binding sheets of paper formed with two or more holes, and more particularly is directed towards a new and improved binder which readily accommodates a stack of paper of different thicknesses and which prevents accidental separation of sheets from the binder.
2. Description of the Prior Art
It is common practice to bind together loose sheets of papers, often to a heavy backing sheet or in a folder, by punching two holes in the upper or side margins of the sheets and binding them to a folder by means of a fastener comprised of a relatively thin strip of metal having a cross piece and a pair of forwardly projecting tabs. The tabs extend through the punched holes and are adapted to fold over on top of the stack of paper to secure the stack in place. A compressor bar in the form of a plate with an opening at each end may be added and slide rings may be utilized to hold the tabs flat against the compressor bar.
While such devices have been in common use for many years, they suffer from certain disadvantages. For example, the thin strips of metal tend to cut into the paper so that sheets in a bound stack of papers which is in frequent use tend to become torn, particularly around the punched holes, allowing sheets to separate from the stack. Also, the metal strips tend to be rather sharp and a person using such devices may cut his hands if he is not careful. A more serious drawback of prior art devices is that when papers are being stacked onto the device, the top most sheets easily become displaced, until all papers are in place and the binder locked. Furthermore, the separation of an inner sheet from the stack is extremely difficult since those papers on top of the stack must first be removed, the selected sheet or sheets separated and the papers restacked. Since restacking involves threading the tabs back through the holes, particular care must be taken to keep the holes in registration.
Accordingly, it is an object of the present invention to provide improvements in binders for sheets of paper having preformed holes.
Another object of this invention is to provide improvements in binding devices for stacks of paper which allow easy separation of inner sheets without disturbing the alignment of other sheets thereon.
Still another object of this invention is to provide a device for binding a stack of paper which locks each sheet onto the device when placed thereon.